Guide vanes of this type for turbomachines are already known from the related art. The guide vanes are configured in a compressor or a turbine of the turbomachine, in particular a thermal gas turbine, in such a way that they are fixed relative to a housing of the turbomachine. The turbomachine also includes a plurality of rotating rotor blades that are assigned to at least one rotor and rotate relative to the fixed guide vanes, as well as the stationary housing. Moreover, the guide vanes are coupled to a radially inwardly disposed, static inner ring. To enhance the efficiency of the turbomachine, the guide vanes, which are fixed relative to the rotor blades, can be displaceably, respectively pivotably configured about a radial axis. What is generally referred to as a trailing edge gap is thereby produced in each case between the inner side of the housing and a radially outer, upper trailing edge of the guide vane, respectively between the inner ring and the radially inner, lower trailing edge of the guide vane. The size of the trailing edge gap is dependent on the angular position of the guide vane. The greater the dimensions of the trailing edge gap, the more negative the effect thereof on the efficiency and the surge limit of the turbomachine. This arises, in particular, from the fact that the trailing edges are circumflowed by the working medium of the turbomachine, in particular, by air.